1. Field
The technical field relates to a battery pack and a method of controlling the same, and more particularly, to a battery pack for performing cell balancing of the battery pack and a method of controlling the battery pack.
2. Description of the Related Technology
In general, research into rechargeable batteries has been actively conducted due to the development of portable electronic devices such as cellular phones, laptop computers, camcorders, personal digital assistants (PDAs), and the like. In particular, such rechargeable batteries may be any of various types such as a nickel-cadmium battery, a lead storage battery, a nickel metal hydride battery (NiMH), a lithium ion battery, a lithium polymer battery, a metal lithium battery, or an air zinc battery. A rechargeable battery may be combined with a circuit so as to constitute a battery pack and is charged and discharged through an external terminal of the battery pack.
A general battery pack includes a battery cell and a peripheral circuit including a charge-discharge circuit, wherein the peripheral circuit is prepared as a printed circuit board and is combined with the battery cell. When an external power source is connected to an external terminal of the battery pack, the battery cell is charged by external power supplied through the external terminal and the charge-discharge circuit. When a load is connected to the external terminal, power of the battery cell is supplied to the load through the charge-discharge circuit and the external terminal. In this regard, the charge-discharge circuit controls charge and discharge of the battery cell occurring between the external terminal and the battery cell. In general, a plurality of battery cells are connected in series or in parallel, according to consumption of a load, to provide power to a device.
Respective battery cells constituting a battery pack have a capacity deviation due to variations in a manufacturing process. Accordingly, in a battery pack, deviations occur in a charge-discharge voltage of each battery cell during a charge-discharge cycle. Thus, in a battery pack, a specific battery cell may be over-charged during the charging, and a specific battery cell may be over-discharged during the discharging. As such, the over-charge or over-discharge of the specific battery cell in the battery pack reduces the capacity of the battery pack, degrades the battery pack, and shortens the lifespan of the battery pack.